Do Sharks Sleep?

Photo by Jakob Owens on Unsplash

Have you ever wonder if sharks sleep?

For sharks to keep receiving oxygen, water needs to be kept in constant motion over their gills. This indirectly means that they will need to be in a state of constant motion. But does this mean that sharks must never stop moving, and by implication will never sleep?

Will a shark die if it stops moving?

This may be true for some sharks, while it’s not so for some sharks. Some sharks need to remain in motion to allow water to cover their gills. However, some sharks have spiracles. This structure allows them to breathe while lying down at the bottom of the ocean. It allows them to breathe well while in a state of rest.

Do they sleep?

Sharks that need to be in motion to make breathing possible have their active periods and their resting period. However, they do not sleep as we do, but they seem to be sleeping while in motion. At this moment, a portion of their brain becomes less active which fulfils the portion of the dictionary’s description of sleep- “suspending consciousness.”

Research shows that sharks do not use their brains for movement, but their spinal cords coordinate the whole process of swimming. This means that they can do swimming while being unconscious.

So, sharks actually fulfill the dictionary’s description of what it means to sleep, except that they don’t sleep as human do.